Positron Emission Tomography (PET) is a functional imaging technique with potential to quantify the rates of biological processes in vivo. The availability of short lived positron-emitting isotopes of carbon, nitrogen, oxygen and especially fluorine allows virtually any compound of biological interest to be labeled in trace amounts and introduced into the body for imaging with PET. The distribution of the tracer is imaged dynamically, allowing the rates of biological processes to be calculated using appropriate mathematical models. PET imaging can provide diagnosis for symptoms of diseases such as Alzheimer's disease, head trauma, and stroke. PET technology is also playing a prominent and an increasingly visible role in modern cancer research, clinical diagnosis and oncology. While PET is a powerful imaging tool, the performance of current clinical PET systems is limited by the available detector technology and there is an urgent need for improvement in PET instrumentation in order to exploit the full potential of this promising technique. The goal of the proposed effort is to design, build and implement new, solid-state photodetectors for reading out scintillation crystals in PET imaging. [unreadable] [unreadable] [unreadable]